Andrew's git / gitweb.git / git-difftool.perl
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git-difftool.perlon commit show-ref: make --head always show the HEAD ref (3f3d0ce)
   1#!/usr/bin/perl
   2# Copyright (c) 2009, 2010 David Aguilar
   3# Copyright (c) 2012 Tim Henigan
   4#
   5# This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
   6# git-difftool--helper script.
   7#
   8# This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
   9# The GIT_DIFF* variables are exported for use by git-difftool--helper.
  10#
  11# Any arguments that are unknown to this script are forwarded to 'git diff'.
  12
  13use 5.008;
  14use strict;
  15use warnings;
  16use File::Basename qw(dirname);
  17use File::Copy;
  18use File::Compare;
  19use File::Find;
  20use File::stat;
  21use File::Path qw(mkpath rmtree);
  22use File::Temp qw(tempdir);
  23use Getopt::Long qw(:config pass_through);
  24use Git;
  25
  26sub usage
  27{
  28        my $exitcode = shift;
  29        print << 'USAGE';
  30usage: git difftool [-t|--tool=<tool>] [--tool-help]
  31                    [-x|--extcmd=<cmd>]
  32                    [-g|--gui] [--no-gui]
  33                    [--prompt] [-y|--no-prompt]
  34                    [-d|--dir-diff]
  35                    ['git diff' options]
  36USAGE
  37        exit($exitcode);
  38}
  39
  40sub find_worktree
  41{
  42        my ($repo) = @_;
  43
  44        # Git->repository->wc_path() does not honor changes to the working
  45        # tree location made by $ENV{GIT_WORK_TREE} or the 'core.worktree'
  46        # config variable.
  47        my $worktree;
  48        my $env_worktree = $ENV{GIT_WORK_TREE};
  49        my $core_worktree = Git::config('core.worktree');
  50
  51        if (defined($env_worktree) and (length($env_worktree) > 0)) {
  52                $worktree = $env_worktree;
  53        } elsif (defined($core_worktree) and (length($core_worktree) > 0)) {
  54                $worktree = $core_worktree;
  55        } else {
  56                $worktree = $repo->wc_path();
  57        }
  58
  59        return $worktree;
  60}
  61
  62sub print_tool_help
  63{
  64        my $cmd = 'TOOL_MODE=diff';
  65        $cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
  66        $cmd .= ' && show_tool_help';
  67
  68        # See the comment at the bottom of file_diff() for the reason behind
  69        # using system() followed by exit() instead of exec().
  70        my $rc = system('sh', '-c', $cmd);
  71        exit($rc | ($rc >> 8));
  72}
  73
  74sub exit_cleanup
  75{
  76        my ($tmpdir, $status) = @_;
  77        my $errno = $!;
  78        rmtree($tmpdir);
  79        if ($status and $errno) {
  80                my ($package, $file, $line) = caller();
  81                warn "$file line $line: $errno\n";
  82        }
  83        exit($status | ($status >> 8));
  84}
  85
  86sub setup_dir_diff
  87{
  88        my ($repo, $workdir, $symlinks) = @_;
  89
  90        # Run the diff; exit immediately if no diff found
  91        # 'Repository' and 'WorkingCopy' must be explicitly set to insure that
  92        # if $GIT_DIR and $GIT_WORK_TREE are set in ENV, they are actually used
  93        # by Git->repository->command*.
  94        my $repo_path = $repo->repo_path();
  95        my %repo_args = (Repository => $repo_path, WorkingCopy => $workdir);
  96        my $diffrepo = Git->repository(%repo_args);
  97
  98        my @gitargs = ('diff', '--raw', '--no-abbrev', '-z', @ARGV);
  99        my $diffrtn = $diffrepo->command_oneline(@gitargs);
 100        exit(0) unless defined($diffrtn);
 101
 102        # Build index info for left and right sides of the diff
 103        my $submodule_mode = '160000';
 104        my $symlink_mode = '120000';
 105        my $null_mode = '0' x 6;
 106        my $null_sha1 = '0' x 40;
 107        my $lindex = '';
 108        my $rindex = '';
 109        my %submodule;
 110        my %symlink;
 111        my @working_tree = ();
 112        my @rawdiff = split('\0', $diffrtn);
 113
 114        my $i = 0;
 115        while ($i < $#rawdiff) {
 116                if ($rawdiff[$i] =~ /^::/) {
 117                        warn << 'EOF';
 118Combined diff formats ('-c' and '--cc') are not supported in
 119directory diff mode ('-d' and '--dir-diff').
 120EOF
 121                        exit(1);
 122                }
 123
 124                my ($lmode, $rmode, $lsha1, $rsha1, $status) =
 125                        split(' ', substr($rawdiff[$i], 1));
 126                my $src_path = $rawdiff[$i + 1];
 127                my $dst_path;
 128
 129                if ($status =~ /^[CR]/) {
 130                        $dst_path = $rawdiff[$i + 2];
 131                        $i += 3;
 132                } else {
 133                        $dst_path = $src_path;
 134                        $i += 2;
 135                }
 136
 137                if ($lmode eq $submodule_mode or $rmode eq $submodule_mode) {
 138                        $submodule{$src_path}{left} = $lsha1;
 139                        if ($lsha1 ne $rsha1) {
 140                                $submodule{$dst_path}{right} = $rsha1;
 141                        } else {
 142                                $submodule{$dst_path}{right} = "$rsha1-dirty";
 143                        }
 144                        next;
 145                }
 146
 147                if ($lmode eq $symlink_mode) {
 148                        $symlink{$src_path}{left} =
 149                                $diffrepo->command_oneline('show', "$lsha1");
 150                }
 151
 152                if ($rmode eq $symlink_mode) {
 153                        $symlink{$dst_path}{right} =
 154                                $diffrepo->command_oneline('show', "$rsha1");
 155                }
 156
 157                if ($lmode ne $null_mode and $status !~ /^C/) {
 158                        $lindex .= "$lmode $lsha1\t$src_path\0";
 159                }
 160
 161                if ($rmode ne $null_mode) {
 162                        if ($rsha1 ne $null_sha1) {
 163                                $rindex .= "$rmode $rsha1\t$dst_path\0";
 164                        } else {
 165                                push(@working_tree, $dst_path);
 166                        }
 167                }
 168        }
 169
 170        # Setup temp directories
 171        my $tmpdir = tempdir('git-difftool.XXXXX', CLEANUP => 0, TMPDIR => 1);
 172        my $ldir = "$tmpdir/left";
 173        my $rdir = "$tmpdir/right";
 174        mkpath($ldir) or exit_cleanup($tmpdir, 1);
 175        mkpath($rdir) or exit_cleanup($tmpdir, 1);
 176
 177        # If $GIT_DIR is not set prior to calling 'git update-index' and
 178        # 'git checkout-index', then those commands will fail if difftool
 179        # is called from a directory other than the repo root.
 180        my $must_unset_git_dir = 0;
 181        if (not defined($ENV{GIT_DIR})) {
 182                $must_unset_git_dir = 1;
 183                $ENV{GIT_DIR} = $repo_path;
 184        }
 185
 186        # Populate the left and right directories based on each index file
 187        my ($inpipe, $ctx);
 188        $ENV{GIT_INDEX_FILE} = "$tmpdir/lindex";
 189        ($inpipe, $ctx) =
 190                $repo->command_input_pipe(qw(update-index -z --index-info));
 191        print($inpipe $lindex);
 192        $repo->command_close_pipe($inpipe, $ctx);
 193
 194        my $rc = system('git', 'checkout-index', '--all', "--prefix=$ldir/");
 195        exit_cleanup($tmpdir, $rc) if $rc != 0;
 196
 197        $ENV{GIT_INDEX_FILE} = "$tmpdir/rindex";
 198        ($inpipe, $ctx) =
 199                $repo->command_input_pipe(qw(update-index -z --index-info));
 200        print($inpipe $rindex);
 201        $repo->command_close_pipe($inpipe, $ctx);
 202
 203        $rc = system('git', 'checkout-index', '--all', "--prefix=$rdir/");
 204        exit_cleanup($tmpdir, $rc) if $rc != 0;
 205
 206        # If $GIT_DIR was explicitly set just for the update/checkout
 207        # commands, then it should be unset before continuing.
 208        delete($ENV{GIT_DIR}) if ($must_unset_git_dir);
 209        delete($ENV{GIT_INDEX_FILE});
 210
 211        # Changes in the working tree need special treatment since they are
 212        # not part of the index
 213        for my $file (@working_tree) {
 214                my $dir = dirname($file);
 215                unless (-d "$rdir/$dir") {
 216                        mkpath("$rdir/$dir") or
 217                        exit_cleanup($tmpdir, 1);
 218                }
 219                if ($symlinks) {
 220                        symlink("$workdir/$file", "$rdir/$file") or
 221                        exit_cleanup($tmpdir, 1);
 222                } else {
 223                        copy("$workdir/$file", "$rdir/$file") or
 224                        exit_cleanup($tmpdir, 1);
 225
 226                        my $mode = stat("$workdir/$file")->mode;
 227                        chmod($mode, "$rdir/$file") or
 228                        exit_cleanup($tmpdir, 1);
 229                }
 230        }
 231
 232        # Changes to submodules require special treatment. This loop writes a
 233        # temporary file to both the left and right directories to show the
 234        # change in the recorded SHA1 for the submodule.
 235        for my $path (keys %submodule) {
 236                my $ok;
 237                if (defined($submodule{$path}{left})) {
 238                        $ok = write_to_file("$ldir/$path",
 239                                "Subproject commit $submodule{$path}{left}");
 240                }
 241                if (defined($submodule{$path}{right})) {
 242                        $ok = write_to_file("$rdir/$path",
 243                                "Subproject commit $submodule{$path}{right}");
 244                }
 245                exit_cleanup($tmpdir, 1) if not $ok;
 246        }
 247
 248        # Symbolic links require special treatment. The standard "git diff"
 249        # shows only the link itself, not the contents of the link target.
 250        # This loop replicates that behavior.
 251        for my $path (keys %symlink) {
 252                my $ok;
 253                if (defined($symlink{$path}{left})) {
 254                        $ok = write_to_file("$ldir/$path",
 255                                        $symlink{$path}{left});
 256                }
 257                if (defined($symlink{$path}{right})) {
 258                        $ok = write_to_file("$rdir/$path",
 259                                        $symlink{$path}{right});
 260                }
 261                exit_cleanup($tmpdir, 1) if not $ok;
 262        }
 263
 264        return ($ldir, $rdir, $tmpdir, @working_tree);
 265}
 266
 267sub write_to_file
 268{
 269        my $path = shift;
 270        my $value = shift;
 271
 272        # Make sure the path to the file exists
 273        my $dir = dirname($path);
 274        unless (-d "$dir") {
 275                mkpath("$dir") or return 0;
 276        }
 277
 278        # If the file already exists in that location, delete it.  This
 279        # is required in the case of symbolic links.
 280        unlink($path);
 281
 282        open(my $fh, '>', $path) or return 0;
 283        print($fh $value);
 284        close($fh);
 285
 286        return 1;
 287}
 288
 289sub main
 290{
 291        # parse command-line options. all unrecognized options and arguments
 292        # are passed through to the 'git diff' command.
 293        my %opts = (
 294                difftool_cmd => undef,
 295                dirdiff => undef,
 296                extcmd => undef,
 297                gui => undef,
 298                help => undef,
 299                prompt => undef,
 300                symlinks => $^O ne 'cygwin' &&
 301                                $^O ne 'MSWin32' && $^O ne 'msys',
 302                tool_help => undef,
 303        );
 304        GetOptions('g|gui!' => \$opts{gui},
 305                'd|dir-diff' => \$opts{dirdiff},
 306                'h' => \$opts{help},
 307                'prompt!' => \$opts{prompt},
 308                'y' => sub { $opts{prompt} = 0; },
 309                'symlinks' => \$opts{symlinks},
 310                'no-symlinks' => sub { $opts{symlinks} = 0; },
 311                't|tool:s' => \$opts{difftool_cmd},
 312                'tool-help' => \$opts{tool_help},
 313                'x|extcmd:s' => \$opts{extcmd});
 314
 315        if (defined($opts{help})) {
 316                usage(0);
 317        }
 318        if (defined($opts{tool_help})) {
 319                print_tool_help();
 320        }
 321        if (defined($opts{difftool_cmd})) {
 322                if (length($opts{difftool_cmd}) > 0) {
 323                        $ENV{GIT_DIFF_TOOL} = $opts{difftool_cmd};
 324                } else {
 325                        print "No <tool> given for --tool=<tool>\n";
 326                        usage(1);
 327                }
 328        }
 329        if (defined($opts{extcmd})) {
 330                if (length($opts{extcmd}) > 0) {
 331                        $ENV{GIT_DIFFTOOL_EXTCMD} = $opts{extcmd};
 332                } else {
 333                        print "No <cmd> given for --extcmd=<cmd>\n";
 334                        usage(1);
 335                }
 336        }
 337        if ($opts{gui}) {
 338                my $guitool = Git::config('diff.guitool');
 339                if (length($guitool) > 0) {
 340                        $ENV{GIT_DIFF_TOOL} = $guitool;
 341                }
 342        }
 343
 344        # In directory diff mode, 'git-difftool--helper' is called once
 345        # to compare the a/b directories.  In file diff mode, 'git diff'
 346        # will invoke a separate instance of 'git-difftool--helper' for
 347        # each file that changed.
 348        if (defined($opts{dirdiff})) {
 349                dir_diff($opts{extcmd}, $opts{symlinks});
 350        } else {
 351                file_diff($opts{prompt});
 352        }
 353}
 354
 355sub dir_diff
 356{
 357        my ($extcmd, $symlinks) = @_;
 358        my $rc;
 359        my $error = 0;
 360        my $repo = Git->repository();
 361        my $workdir = find_worktree($repo);
 362        my ($a, $b, $tmpdir, @worktree) =
 363                setup_dir_diff($repo, $workdir, $symlinks);
 364
 365        if (defined($extcmd)) {
 366                $rc = system($extcmd, $a, $b);
 367        } else {
 368                $ENV{GIT_DIFFTOOL_DIRDIFF} = 'true';
 369                $rc = system('git', 'difftool--helper', $a, $b);
 370        }
 371        # If the diff including working copy files and those
 372        # files were modified during the diff, then the changes
 373        # should be copied back to the working tree.
 374        # Do not copy back files when symlinks are used and the
 375        # external tool did not replace the original link with a file.
 376        for my $file (@worktree) {
 377                next if $symlinks && -l "$b/$file";
 378                next if ! -f "$b/$file";
 379
 380                my $diff = compare("$b/$file", "$workdir/$file");
 381                if ($diff == 0) {
 382                        next;
 383                } elsif ($diff == -1) {
 384                        my $errmsg = "warning: Could not compare ";
 385                        $errmsg += "'$b/$file' with '$workdir/$file'\n";
 386                        warn $errmsg;
 387                        $error = 1;
 388                } elsif ($diff == 1) {
 389                        my $mode = stat("$b/$file")->mode;
 390                        copy("$b/$file", "$workdir/$file") or
 391                        exit_cleanup($tmpdir, 1);
 392
 393                        chmod($mode, "$workdir/$file") or
 394                        exit_cleanup($tmpdir, 1);
 395                }
 396        }
 397        if ($error) {
 398                warn "warning: Temporary files exist in '$tmpdir'.\n";
 399                warn "warning: You may want to cleanup or recover these.\n";
 400                exit(1);
 401        } else {
 402                exit_cleanup($tmpdir, $rc);
 403        }
 404}
 405
 406sub file_diff
 407{
 408        my ($prompt) = @_;
 409
 410        if (defined($prompt)) {
 411                if ($prompt) {
 412                        $ENV{GIT_DIFFTOOL_PROMPT} = 'true';
 413                } else {
 414                        $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
 415                }
 416        }
 417
 418        $ENV{GIT_PAGER} = '';
 419        $ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 420
 421        # ActiveState Perl for Win32 does not implement POSIX semantics of
 422        # exec* system call. It just spawns the given executable and finishes
 423        # the starting program, exiting with code 0.
 424        # system will at least catch the errors returned by git diff,
 425        # allowing the caller of git difftool better handling of failures.
 426        my $rc = system('git', 'diff', @ARGV);
 427        exit($rc | ($rc >> 8));
 428}
 429
 430main();